diff options
| author | David Chase <drchase@google.com> | 2018-06-25 15:26:45 -0400 |
|---|---|---|
| committer | David Chase <drchase@google.com> | 2018-06-25 20:36:42 +0000 |
| commit | 7e9d55eeeb183ee95d26b3ed4ff171902605decf (patch) | |
| tree | 5739d3711787f80403e6616d11285454508d7b99 /src/cmd/compile/internal/ssa | |
| parent | 6d709528972aa572a6dafb06cd3446348d337aa7 (diff) | |
| download | go-7e9d55eeeb183ee95d26b3ed4ff171902605decf.tar.xz | |
cmd/compile: avoid remainder in loopbce when increment=0
For non-unit increment, loopbce checks to see if the
increment evenly divides the difference between (constant)
loop start and end. This test panics when the increment
is zero.
Fix: check for zero, if found, don't optimize the loop.
Also added missing copyright notice to loopbce.go.
Fixes #26043.
Change-Id: I5f460104879cacc94481949234c9ce8c519d6380
Reviewed-on: https://go-review.googlesource.com/120759
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Diffstat (limited to 'src/cmd/compile/internal/ssa')
| -rw-r--r-- | src/cmd/compile/internal/ssa/loopbce.go | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/src/cmd/compile/internal/ssa/loopbce.go b/src/cmd/compile/internal/ssa/loopbce.go index 0c09de0bfc..2ab05711ad 100644 --- a/src/cmd/compile/internal/ssa/loopbce.go +++ b/src/cmd/compile/internal/ssa/loopbce.go @@ -1,3 +1,7 @@ +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + package ssa import "fmt" @@ -154,7 +158,7 @@ nextb: // if the increment is ±1 or when the limits are constants. if inc.AuxInt != 1 && inc.AuxInt != -1 { ok := false - if min.Op == OpConst64 && max.Op == OpConst64 { + if min.Op == OpConst64 && max.Op == OpConst64 && inc.AuxInt != 0 { if max.AuxInt > min.AuxInt && max.AuxInt%inc.AuxInt == min.AuxInt%inc.AuxInt { // handle overflow ok = true } |